This invention generally relates to processes and equipment for producing wire, such as wire for use as feedstock in welding and coating deposition processes. More particularly, this invention relates to a process and apparatus for forming wire through the application of microwave energy on a powder.
Conventional uses for wires (including rods and filaments) include structural uses such as bearing mechanical loads, electrical uses for carrying electrical currents and telecommunications signals, and as feedstock for a variety of processes. Examples of feedstock usage include certain thermal spray processes such as wire arc spray, certain welding processes such as gas tungsten arc welding (GTAW), plasma arc welding (PAW), and laser beam welding (LBW), and certain physical vapor deposition (PVD) processes. Common processes for producing wires include drawing, rolling, extrusion, sintering powders, and bonding powders together with a binder. The wires may have a homogeneous construction and composition, or may comprise a sheath surrounding a core that may be in the form of a solid bulk, loose or sintered powders, or strands formed of a material that may be the same or different from the sheath material. For example, shielded metal arc welding (SMAW) processes employ a solid metal wire encapsulated in a non-metallic sheath formed of a flux material that forms a protective slag over the molten weld puddle during the welding operation. Wires comprising a powder enclosed in a sheath have been fabricated by rolling, drawing, and extrusion processes, such as by placing a powder in a continuous metallic strip and then closing the strip around the powder in a manner that forms a continuous consolidated sheath.
While the above wire production methods have been successfully employed for many years, there is an ongoing need for methods that are simpler, require less extensive equipment, and capable of producing wires that are difficult to fabricate by conventional methods.